|  | 2.2 |
Full-Duplex Transmitting, Fast Ethernet Standard and LAN Segmentation
| 2.2.4 | The pros and cons of LAN segmentation with routers
Routers are more advanced than typical bridges. A bridge is passive on the network and operates at the data link layer. A router operates at the network layer and bases all its decisions about forwarding between segments on the network-layer protocol address. Routers create the highest level of segmentation by forwarding data to the hub, to which workstations are connected. A router makes forwarding decisions to segments by examining the destination address on the data packet and looking in its routing table for forwarding instructions. A router must examine a packet to determine the best path for forwarding that packet to its destination. This process takes time. Protocols that require an acknowledgement from the receiver to the sender for every packet as it is delivered (known as acknowledgement-oriented protocols) have a 30%-40% loss of throughput. Protocols that require minimal acknowledgements (sliding-window protocols) suffer a 20%-30% loss of throughput. This is due to the fact that there is less data traffic between the sender and receiver (that is, fewer acknowledgements).